Abstract

Impurity-free disordering (IFD) of uniformly dopedepitaxial layers was achieved using either undoped or doped (Ga or P) spin-on-glass (SOG) in conjunction with rapid thermal annealing in the temperature range from . Capacitance-voltage measurements showed a pronounced increase in the doping concentration in the near-surface region of the layers disordered using both undoped and P:SOG. The increase in showed an Arrhenius-like dependence on the inverse of annealing temperature. On the other hand, did not change significantly for Ga-doped SOG. These changes can be explained by the relative injection of excess gallium vacancies during IFD of by the different SOG layers. Deep-level transient spectroscopy showed a corresponding increase in the concentration of a defect HA , which can be attributed to Cu, in the undoped and P:SOG disordered layers, but not in the epilayers disordered by Ga:SOG. We have explained the increase in free carrier concentration by the segregation of Zn atoms towards the surface during the injection of . The redistribution of Zn during disordering of buried marker layers in GaAs and using either undoped or Ga-doped SOG was verified by secondary-ion mass spectrometry.

Received 26 April 2004Accepted 09 November 2004Published online 19 January 2005

Acknowledgments:

One of the authors (P. N. K. D.) acknowledges the financial support of the Australian Research Council. A second (F. D. A.) is grateful to the National Research Foundation, South Africa, for its financial support.